Do in vitro susceptibility data predict the microbiologic response to amphotericin B? Results of a prospective study of patients with Candida fungemia

J Infect Dis. 1998 Feb;177(2):425-30. doi: 10.1086/514193.


Outcome for 105 patients with candidemia treated with amphotericin B was correlated with amphotericin B in vitro susceptibility results. Thirty-three patients had microbiologic failure, which was defined as persistence of Candida in the bloodstream despite > or = 3 days of amphotericin B. Amphotericin B minimum inhibitory concentrations (MICs) were determined by the National Committee for Clinical Laboratory Standards methodology. After determination of MICs, the minimal lethal concentrations (MLCs) were determined. The isolates tested yielded a narrow range of amphotericin B MICs (0.06-2 microg/mL); only 5% (5/105) exhibited MICs > or = 1 microg/mL. The MLC range, on the other hand, was significantly broader (0.125 to > 16 microg/mL); 24% (25/105) exhibited MLCs > or = 1 microg/mL. The strongest predictor for microbiologic failure was 48-h MLC (P < .001), followed by 24-h MLC (P = .03) and 48-h MIC (P = .11). A resistant break point for amphotericin B of > 1 microg/mL for MLC and > or = 1 microg/mL for MIC could be inferred from this study.

MeSH terms

  • Amphotericin B / pharmacology*
  • Amphotericin B / therapeutic use
  • Antifungal Agents / pharmacology*
  • Antifungal Agents / therapeutic use
  • Candida / drug effects*
  • Candidiasis / drug therapy*
  • Drug Resistance, Microbial
  • Fungemia / drug therapy*
  • Humans
  • Microbial Sensitivity Tests
  • Predictive Value of Tests
  • Sensitivity and Specificity
  • Treatment Failure
  • Treatment Outcome


  • Antifungal Agents
  • Amphotericin B